Thanks!
Yes, this works but again i don't have the symbols.

If i type 'file executable' the gdb kills the current session and loads the symbols (but when i will be in remote environment??) but the gdbserver exits
If i re-run the server gdb shows me the source correctly.
Is there a way to avoid all this operations on them and launch a complete debugging session?

If i should be in a real remote debugging session, the gdb have to see the executable loaded on the target? So, both of them have to see the executable?

Thanks a lot!